Processing film units in sheet form

ABSTRACT

A rack for use with a liquid tight container wherein solutions used in photographic processing are retained. The rack enables a user to process a plurality of film units in sheet form and includes a novel structure in which the film units are securely retained in compartments in a spaced relationship with an emulsion side of each film unit protected against abrasion during processing and subsequent handling thereof. The rack is particularly adapted to process already-developed-and-set-image negative components of so-called positive-negative film (e.g., Type 55 P/N and Type 105 P/N film sold by Polaroid Corporation, Cambridge, Mass. U.S.A.) after the separation thereof from a positive component whereby residual developer is cleared from the emulsion side. The rack permits the user to conduct each step of the photographic processing without removing the film units therefrom and offers protection against skin irritating photographic chemicals during handling.

United States Patent Cutler, Jr.

[ Feb. 25, 1975 PROCESSING FILM UNITS IN SHEET FORM [75] lnventor: Norman W. Cutler, Jr., Braintree,

Mass.

[73] Assignee: Polaroid Corporation, Cambridge,

Mass.

[22] Filed: Mar. 4, 1974 [21] Appl. No.: 447,570

[52] [1.8. CI. 354/340, 211/45 [51] Int. Cl. G03d 13/08 [58] Field of Search 354/297, 307, 311, 312, 354/316, 331, 335, 340, 342, 344, 346; 211/45, 50, 55

[56] References Cited UNITED STATES PATENTS 902,940 11/1908 Carkhuff 354/344 X 1,158,879 11/1915 Wilson 354/335 1,194,321 8/1916 Randall 354/344 1,661,378 3/1928 McKellar... 354/344 2,461,289 2/1949 Mancuso.... 354/312 3,521,545 7/1970 Buechner... 354/331 X 3,741,099 6/1973 Buckley 354/344 X Primary ExaminerFred L. Braun Attorney, Agent, or Firm-Kenneth W. Anderson [57] ABSTRACT A rack for use with a liquid tight container wherein solutions used in photographic processing are retained. The rack enables a user to process a plurality of film units in sheet form and includes a novel structure in which the film units are securely retained in compartments in a spaced relationship with an emulsion side of each film unit protected against abrasion during processing and subsequent handling thereof. The rack is particularly adapted to process alreadydeveloped-and-set-image negative components of socalled positive-negative film (e.g., Type 55 PIN and Type 105 P/N film sold by Polaroid Corporation, Cambridge, Mass. USA.) after the separation thereof from a positive component whereby residual developer is cleared from the emulsion side. The rack permits the user to conduct each step of the photographic processing without removing the film units therefrom and offers protection against skin irritating photographic chemicals during handling.

10 Claims, 4 DrawingFigures PROCESSING FILM UNITS IN SHEETFORM BACKGROUND OF THE INVENTION 1. Field of the invention This invention relates to a removable rack for use with a liquid tight container wherein film units in sheet form are processed.

2. Description of the Prior Art Good photographs are seen in a minds eye before a cameras shutter is tripped, but they are made during subsequent processing of each film unit. It is in final stages of photography in producing negatives and photographic prints that creative vision is realized in a photograph meant to be looked at and admired. The technical skills demanded of a printmaker are simple. Modern chemical compounds, processing tanks and printing devices lend themselves to procedures which have eliminated guesswork thereby arousing interest in amateur photographers to pursue processing of their own negatives and photographic prints. The skills needed to develop good negatives are quickly learned and the equipment demanded is modest. Most amateurs conduct film processing within temporary work areas designed in a kitchen or a bathroom wherein a sink with running water is available for use in washing negatives and prints and provides a convenience whereby other steps required in processing may be performed. Professional photographers generally have more suitable facilities and more elaborate equipment available for use in processing film units wherein the bathroom sink is replaced by a developing tank, and a plurality of tanks or trays containing a variety of processing solutions are sequentially arranged.

Amateur or professional, the photographer employs similar techniques and processing solutions to acquire a superior negative and photographic print. A number of factors effect the negatives image-molding process. A complicated solution containing several chemicals, a developer, is an active molder of the image. Equally important are final steps of the process which include: a stop bath which applies a chemical brake to halt development quickly; a fixer for dissolving leftover emulsion crystals before they have an opportunity to darken; and finally, clean water for washing away chemicals which may injure the image.

Total darkness is required when the film, in roll or in sheet form, is loaded into the developing tank. Upon loading the film into the developing tank, the tank is closed up and each remaining step of a developing process can be carried out in ordinary room illumination as long as the cover remains on the developing tank. Most developing tanks include a capped opening for receiving and subsequently draining processing solutions from the developing tank without subjecting the film contained therein to any light. Thus the film may be subjected to the developer, stop bath, and finally the fixer by pouring in and draining out each processing solution in proper sequence. When the fixer is drained from the tank, the developing tanks cover may be removed as the film is no longer sensitive to light. The fixer sets the image permanently on the film whereby the negative is formed for printmaking.

Too often the photographer is lulled into false security by the term fixed." A most carefully prepared negative can fade or turn yellow if not thoroughly washed. Great care must be taken in washing the film to protect the negatives emulsion side as it is relatively soft when soaked in water and if not properly protected from contact with other negatives or objects. the emulsion side of the film may be impairably damaged. Such damage is more apt to happen in a case wherein unrestrained sheet films are washed in the conventional developing tank without some form of a holder. The washing must not be taken casually. The water must be clean, and the negatives restrained from movement in the tank when the tank is agitated to assure removal of all of the fixer from the film thereby preventing sulfur compounds included therein from tarnishing silver crystals of the negatives image. Another method commonly used in washing is to place the negative under a faucet and allow the water flowing therefrom to run slowly over the film into the sink but great care must be taken to control the flow of the water as too much force can damage the emulsion side of the negative.

The emulsion is still wet and soft and may be easily scratched when the washing has been completed and the film is hung up to air dry. The negative must be handled delicately during the drying period and protected from dust which may attach itself to the negative whereby dust spots will appear upon the finished print. Clips and hangers are generally used as a means for hanging the negatives up to air dry whereby the negatives are suspended therefrom and subject to dust particles included within the room. Hanging the negatives away from walls and windows in the center of the room is considered to be one method of combating an accumulation of dust particles thereupon as this area of the room is usually less plagued by dust particles.

The processing of sheet films follows the same processing steps and is generally carried out in open trays by the amateur photographer due to an expense occurred in purchasing a special developing tank which may not be adapted for use in developing roll film. Each film sheet is handled with tweezer-like tongs whereby the film sheet may be removed from one tray and placed into an adjoining tray containing the necessary processing solution. The photographer must be careful not to scratch the film sheet during handling, especially when the film sheet is removed from the fixer and the washing process begins, as the emulsion is wet, soft and easily scratched. The film sheet, now in negative form, is more often than not difficult to grip and handle properly with tongs. If the kitchen or bathroom is used as a part-time darkroom, particular care must be taken, when open trays are used, with photographic chemicals. Photographic chemicals are potent substances; many of which stain flooring and textiles, a few are poisonous, and some may cause skin irritations.

The word darkroom is something of a misnomer. Bright room lights may be left on after the film has been removed from the fixer whereby the remaining steps of development may be carried out. Printmaking is carried out in the illumination ofa yellow, green or amber safelight which emits light of a color that does not effect a set-image negative or printing paper. Printmaking is conducted in open trays and each print is handled by the tweezer-like tongs during the developing process. Like film, printing paper is coated with a lightsensitive emulsion. A light is passed through the negative onto the printing paper and exposed whereupon the individual exposed sheet of printing paper is placed into an open tray containing a developer for several minutes so that chemical action can convert into metallic silver those crystals which have been exposed to the light; it is next transferred to a stop bath to halt the action of the developer, then placed in a fixer which removes undeveloped and unexposed crystals, and finally washed and dried. The tongs are used to transfer individual sheets of print paper from one open tray to another and to entirely immerse and hold the print paper therein. Further uses of the tongs are to lift the print paper from the open'tray so that the processing solution can drain into the open tray preventing the processing solution from contaminating the processing solution in a second open tray, and to move the print about to and fro whereby the processing solution is agitated. It is of extreme importance for the tongs to be properly rinsed after use with one photographic chemical or confined to use with only one solution thereby preventing contamination of a solution in a second open tray when each processing step is performed. The final steps in processing are important for if they are skimped, the final print may fade or discolor. Washing particularly, should not be hurried and performed with extreme care. The print must be washed for at leaast 60 minutes to remove all traces of the fixer. If any remains, the print may then yellow. Finally, the print is air dried in a similar manner described previously for air drying the negative.

Developing film sheets and engaging in print-making is generally performed by the photographer handling each film unit separately, using the tongs as described whereby careless handling of the film unit may lead to undesired scratching of the negative or print. Racks for storing a plurality of film units during chemical processing of the film units have been suggested for use in developing tanks to protect the film units during the developing process. Such racks have generally failed to include thereon a handle whereby the rack may be conveniently immersed and withdrawn from the processing solutions, transported and hung up to air dry with the film units contained therein. Such a handle would also provide a convenient means for lifting the rack from within, and lowering the rack into, the processing solution when individual film units are located therein and prevents buckling of the film units during insertion into the container when filled with the processing solution.

The photographic chemicals used in processing may cause skin irritations and a few are poisonous as previously mentioned thereby encouraging the least amount of contact to be made with a person conducting the processing. The use of tongs with open trays and prior art devices have failed to offer such protection. As illustrative of such a prior art device, mention may be made of US. Pat. No. 1,194,321 wherein a handle is not provided. Reference is made to a pair of flanges adjacent to side walls of the rack whereby the rack may be gripped and moved as a unit. As such, the rack is not adapted for a quick transfer of the rack from one container to another. The flanges fail to provide a secure means for handling a rack which has been immersed into a variety of chemical solutions whereby a slippery coating of the solution will prevent firm gripping of the rack and offers little protection from contact with the skin irritating chemicals. Other prior art devices such as the invention shown in US. Pat. No. 3,741,099 include a container having a rack included therein described to be removable but fails to provide any means for handling or lifting the rack without engaging the chemical solution. The invention would also appear to have failed to include support members whereby film units are prevented from passing through the rack should there be an attempted withdrawal thereof.

Inasmuch as the present invention is primarily directed towards a rack for use in a developing process for film units in sheet form; whether in a make shift darkroom, laboratory, or under exacting field conditions, wherein a protective environment is essential and prompt subjection of the film units emulsion to a liquid under agitation is necessary to clear areas having residual developer adhering to an emulsion side of the film unit and retains an emulsion side of the film unit free from contact with other film units or portions of the rack, it will be apparent that means of conventional types would be unsuitable for this purpose. Accordingly, apparatus of the subject invention necessarily involves a somewhat different approach and an employment of special means to effect processing of materials contemplated.

SUMMARY OF THE INVENTION The present invention is addressed to a removable rack for use in storing andprotecting a plurality of film units in sheet form within a liquid tight container during processing and further provides for protective transportation of the film units between any additional processing steps which may be required to process the film units. The rack is used within a container adapted for field and laboratory use and enables a photographer to retain the film units therein protected from dust, stains and scratches. More especially, the rack is adapted to hold set-image negative components of socalled positive-negative film material (Type 55 and Type P/N film sold by Polaroid Corp. of Cambridge, Massachusetts, U.S.A.). Composite film material of this description, characteristically, is exposed, within a camera and upon removal therefrom is developed and fixed within seconds to divide into a positive component and a negative component when the film material is manually separated. The negative component produces a negative having an acetate base side and an emulsion side, the latter being in a still-softened condition when the negative component is stripped from the positive component. I

The container is pre-filled to an indicated level with a predetermined percent of sodium sulfite solution wherein the negative completely immersed within the solution, is cleared of a developer layer and may remain stored therein up to 72 hours without demaging the negative or until a recommended finishing operation can be completed.

The negative produced from the negative component of the film material is already completely developed, has a set-image, and is not light-sensitive. However, the emulsion side of the negative contains an emulsion which is soft and has a layer of developer adhering thereto. Consequently, the negative must be handled carefully to prevent scratches or streaking of the emulsion side. The developer layer retains residualchemical activity and must be removed as quickly as possible from the emulsion side of the negativeto prevent staining or marking of the negatives set-image, namely, within 3 minutes. The rack affords an amateur photographer, working in a temporary, makeshift photographic laboratory, or a professional photographer, working in a well equipped fixed laboratory, to expediently wash and securely hang to air dry a plurality of set-image negatives without undue thought or activity while protecting the negative from dust spots, stains and scratches. v

When printmaking under a fairly bright illumination of a yellow, green or amber safelight, the photographer may store each sheet of a plurality of sheets of exposed printing paper within individual compartments provided in the rack and process the printing paper through each stage of chemical development including washing and air drying without removing the sheets from within the compartments.

The negatives are inserted into the compartments in spaced relationship thereby insuring that the emulsion side of each negative is held out of contact with any part of the rack or with other negatives stored therein. Moreover, the photographer is allowed to pursue work uninterruptedly, under studio or field conditions, accumulating negatives in the rack until each compartment contains one of the negatives whereupon the photographer may remove the rack from the container by grasping a handle attached thereto and insert the rack into a second container having water therein for rinsing the sodium sulfite solution from the negatives without having to touch the negative s damp face. The finishing operation, whereby the negative is prepared for printing, may be conducted wherever water is readily available and required photographic chemicals are stored which may be many hours subsequent to the initial insertion. Containers having an acid hardening solution, rinsing water or a wetting agent sequentially arranged for receiving and processing the negatives can be set up conveniently to enable the photographer to move uninterruptedly through each processing procedure without removing the negatives from the rack. Furthermore, the negatives may be hung to air dry while remaining in the compartments protected from dust, spots, stains and scratches. The handle included on the rack provides a comfortable and secure means for inserting and withdrawing the rack from within each container whereby the photographer may inspect the negatives stored therein and transport the rack. The handle also enables the photographer to lift the rack from within the container before inserting each negative thereby preventing the negative from buckling during the insertion and scratching the emulsion side thereof against a wall of the compartments. It will be apparent that the rack could serve a useful purpose in processing procedures associated with other types of film units wherein separation and protection of sensitive lfilm portions is of special importance.

The rack is formed to provide positive separation and protection for a plurality of film units undergoing process. The film unit is flexed before insertion into one of the compartments provided therein with lateral edges of the flexed film unit positioned within grooves formed by each side wall of the compartments cooperating with a curved wall having a concave surface. The side walls include first portions which extend from lateral edges of the curved walls on the concave side thereof and second portions integral with the first portions and converging towards each other to a convex surface of the next curved wall thereby providing each compartment with a pair of grooves at opposite ends thereof. The base side of the negative, opposite to the emulsion side, is supported by one side of the curved walls whereby the emulsion side is positioned for direct subjection to the processing solution. The curved walls extend uninterruptedly to each of the side walls and are impervious to the passage of the processing solution therethrough whereby the emulsion side of each negative is protected from transmission of sludge and waste particles released from negatives stored in adjacent compartments. The film units are deeply seated within the compartments provided between open upper and lower open faces of the rack whereby the negatives re main captured therein during agitation of the liquid tight container.

The handle may be fixed to the rack or made detachable therefrom and provides a convenient gripping device whereby the rack may be lifted and carried about. The handle is further used as a hanger for supporting the rack when the negatives are hung to air dry. Furthermore, the handle includes a pedestal which spaces the lower face of the rack above the container's base section thereby providing a sump for collecting waste developer or sludge cleared from the emulsion side of the negative. The pedestal further includes supporting members, upon which, each leading edge of any form of film unit first received in the compartment rests and thereby prevents passage of the film unit through the open lower face of the rack. The underside of the supporting members, is recessed above the base of the container to permit circulation of the processing solution through the open lower face of the rack and between compartments. The rack is restrained from lateral movement within the container by frictional contact between inner walls of the container and a plurality of tapering ribs formed on outer walls of the rack. The ribs are tapered in a direction away from the open upper face towards the open lower face of the rack thereby enabling the rack to be properly positioned within the container before frictional contact is made.

Therefore, it is an object of the present invention to provide a readily removable rack for positively holding a plurality of film units and protecting softened emulsions thereof against contact with other film units or with any portion of the rack especially during agitation of the rack.

It is yet another object of the present invention to provide a rack which is especially adapted for processing of a negative produced from a negative component of a so-called positive-negative film and clearing the negative of residual developer after it has been developed and fixed; and yet, may be adapted for use in processing prints and set-image negatives of conventional sheet films.

A further object of the present invention is to provide a rack having a handle whereby the rack may be readily and securely inserted into and withdrawn from a plurality of containers filled with a variety of processing solutions containing irritating chemicals without contact therewith and thereafter hung to air dry to prepare a negative for printing without handling the negative which often results in staining or marking of the negatives image.

A further object and feature of the present invention is to provide a rack which may be adapted for use with a stationary development tank or a liquid tight, light weight portable container for field use whereby a plurality of set-image negatives may be cleared of residual developer and stored therein until running water and other necessary photographic processing chemicals are accessible.

A further object of the present invention is to provide a rack which may be used by amateur and professional photographers having a desire to process set-image negatives and photographic prints and includes a removable handle which is readily attached and detached without undue thought or activity for use with similar racks.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

The invention accordingly comprises the apparatus possessing the construction, combination of elements, and arrangement of parts which are exemplified in the following disclosure and the scope of the application which will be indicated in the claims.

BRIEF DESCRIPTION OF THE DRAWINGS For a fuller understanding of the nature and objects of the invention, reference should be made to the following detailed description taken in conjunction with the accompanying drawings wherein:

FIG. 1 is an exploded view of the instant invention with each member perspectively shown in its related position and a perspective view of a contaianer and cover which may be used therewith;

FIG. 2 is a perspective view of the instant invention shown removed from within the container;

FIG. 3 is a bottom plan view of the instant invention; and

FIG. 4 is a perspective view of the instant invention shown in position within the container having the cover removed and a portion of the container removed for clarity.

DETAILED DESCRIPTION OF THE INVENTION Referring in more detail by reference characters to FIG. 1, a removable rack is illustrated comprising a holder 50 and a handle 42 for withdrawing the rack 10 from within a container 60 whereupon the rack 10 may be readily transported, hung to air dry, inserted into or withdrawn from within the container 60. The holder 50 comprises a chamber 12, having open upper and lower faces 14 and 16, respectively, and attached by bracing members to an insert 22 having a plurality of compartme'nts 40 wherein film units in sheet form may be stored and protectably processed without removing the film units therefrom. A center section 34 of the insert 22 includes a pair of vertical planar end members 36 each having a channel groove 38 formed on opposing faces thereof for slidably receiving therein one edge of upright members 52 of handle 42 whereby holder 50 and handle 42 are coupled to each other to construct the removable rack 10. The handle 42 may also be included as an integral part of holder 50 (as shown in FIG. 2) but is preferably made detachable for re-use with similar holders. When the handle 42 is made detachable, the holder 50 is coupled thereto by centrally positioning the holder 50 above the handle 42 and lowering the holder 50 thereupon engaging edges of upright members 52 within coupling channels 38. The upright members 52 are permitted to slide along a path formed within channel grooves 38 until latching members 48 are engaged thereby whereupon the upright members 52 bow inwardly to permit channel grooves 38 to bypass latching members 48 and re-engage the edges of upright members 52 and the holder 50 is compressively secured between upper surfaces of supporting members 46 and lower edges 54 of latching members 48.

The rack 10 may be used with fixed position developing tanks generally found in a well equipped laboratory of professional photographers and is espeically adapted for use in temporary, makeshift darkrooms of an amateur photographer wherein the amateur photographer temporarily converts his kitchen or bathroom into a photographic laboratory. Film units in sheet form, such as cut negatives and sheet film negatives partially processed to a stage of development wherein an image thereon has been set and the set-image is no longer sensitive to light may be stored within the compartments 40 and subsequent processing procedures continued to prepare the set-image negatives for print-making. The rack 10 lends itself to photographic development processing of contact prints and enlargements of finished negatives upon printing paper. The rack 10, having a film unit stored in each compartment 40, may be immersed into and withdrawn from the container 60, filled with a proper processing solution, by handle 42 and can be washed and finally hung to air dry without requiring the photographer to remove the film units from within the compartments 40 whereby the photographer is protected against skin irritating photographic chemicals of the processing solution.

With the increase in popularity of so-called positivenegative film material, whereby a composite film material is exposed, within a camera and developed and fixed within seconds upon removal therefrom, a negative component of the film material is obtained which provides, after further chemical processing, a set-image negative for future printmaking. The container 60 has a liquid tight seal provided in a snap-cover 62, and a carrying handle 68 whereby the rack 10 immersed in a clearing solution, for removing residual developer from a set-image negative, can accompany the photographer into the field. Thus the photographer is provided with a portable photographic processing laboratory for use with such film material. The container includes a solution level indicator 64 whereby the photographer can fill the container 60 with a clearing solution to a proper level before leaving for the field and be assured the setimage negative inserted into compartments 40 of the rack 10 shall be completely immersed within the clearing solution and a sufficient portion of the handle 42 shall remain above the level indicator 64 to provide se cure handling of the rack 10 and remain out of contact with the clearing solution. The photographer, therefore, is accompanied by a laboratory which permits the photographer to clear the set-image negative of developer immediately after development in the field thereby permitting the photographer to inspect and store the negative component safely until the photographer returns to an area where recommended finishing operations can be completed.

A base end of the handle 42 is joined to a pedestal 56 having a plurality of support members 46 each having a foot-44 and a recessed base 58 adjoining each foot 44. The feet 44 of the pedestal 56 rest upon the container 60s base when the holder and handle 42 are coupled to each other and positioned within the container 60. The holder rests upon upper surfaces of support members 46 (as shown in FIG. 2) above the container s base whereby a sump is formed in the base of the container for receiving sludge and waste particles removed by the processing solutions from the film units. The recessed bases 58 permit the processing solution to circulate beneath the open lower face 16 of the chamber 12 and between compartments 40.

A plurality of tapering ribs 18 are formed upon exterior walls of the chamber 12 for frictionally contacting inner walls of the container 60 when the rack is inserted therein whereby the rack 10 is restrained from lateral movement within the container 60 during agitation.

The removable rack 10, including handle 42, having film units 70 and 80 positioned within the compartments 40 is shown in FIGS. 2 and 3. The rack 10 serves to receive a plurality of the film units 70 and 80 in spaced apart relationship with their emulsion sides 72 and 82, respectively, exposed for free contact with the processing solution. The rack 10 is substantially rigid overall and may be formed of any suitable material, a preferred composition being a plastic substance such as Acrylonitrile Butadiene Styrene. Assuming the aforesaid type of plastic, the rack 10 may be formed by an injection-molding method. It should be understood that, while the holder 50 is illustrated as a unitary component, in other arrangements, it may comprise a plurality of components assembled, or positioned, as required.

The compartments 40 are defined by a plurality of curved vertical supporting walls 24 or partitions joined at lateral edges thereof to a pair of side walls 26. The side walls include first portions 28 extending from the lateral edges of each wall 24 which are joined to second portions 30 converging towards each other to a convex surface of the next of the curved walls 24. The side walls 26 cooperate with the curved walls 24 such that a plurality of vertical grooves 32 are provided at areas contiguous with the curved walls 24 wherein lateral edges 86 of the film unit 80 are supported. The number of compartments provided depends upon a desired overall dimensional limitation of a container or tank.

The curved walls 24 extend uninterruptedly between side walls 26 and are impervious to passage of the processing solution therethrough. As stated hereinabove, the rack 10 has an open upper face 14 for receiving film units 70 and 80 and the open lower face 16 cooperating with the recessed bases 58 to permit circulation of the processing solution through the open lower face 16 and between compartments 40 of the rack 10. The open upper face 14 and open lower face 16 of the rack 10 permit complete circulation of the processing solution within the container 60 during agitation whereby a steady supply of fresh processing solution reaches the emulsion sides 72 and 82 of film units when desired. The continuous wall structure of the curved walls 24 and side walls 26 prevents excessive agitation of the processing solution when carried in the portable container 60.

The film unit 80 is one of a type contemplated for processing and comprises a base side 84 and an emulsion side 82. A linear transverse distance between opposed grooves 32 of the side walls 26 is predeterminedly less than the film units 80's width. Accordingly, the rack 10 is withdrawn from the container 60 to protect the emulsion side 82 of the film unit 80 from damage when an attempt is made to position the low density film unit 80 within the compartment 40 filled with a relatively high density processing solution whereby the film unit 80 will buckle and the emulsion side 82 thereof may contact a surface of one of the walls of the compartment 40. The film unit 80 is flexed and manually inserted into the compartment 40 with the emulsion side 82 facing the center portion 34 of the rack 10. The film unit 80 assumes the approximate curve of curved wall 24 with opposite lateral edges 86 being positioned within the grooves 32 of the side wall 26. Upon so positioning, the film unit 80 is manually released and, as illustrated, is firmly supported on the base side 84 thereof by a concave surface of the curved wall 24, the grooves 32, and when fully inserted into the compartment 40, one edge of the film unit 80 may rest and be supported upon an upper surface of support member 46 whereby the film unit 80 is prevented from passing through the open lower face 16 of the rack 10. The rack 10 thus includes, means 32 for supporting opposed lateral edges 86 of each film unit 80 and means 24 for engaging the base side 84 thereof whereby the lateral edges 86 are urged into the grooves 32. The emulsion side 82 of the film unit 80 is completely out of contact with the curved walls 24 or with any other film units 80 which are, of course, positioned within other compartments 40. The emulsion side 82, accordingly, is adapted to be contacted by the processing solution under agitation as provided, for example, by moving the container gently to and fro.

The film unit is one of another type of film unit contemplated for processing and comprises a base side 74 and an emulsion side 72. The linear transverse distance between opposed grooves 32 of side walls 26 is greater than the width of film units 70. Accordingly, the rack 10 is withdrawn from the container 60 to prevent buckling of the film unit 70 and the film unit is manually inserted into the compartment 40 with the emulsion side 72 facing away from the center portion 34 of the rack 10. The film unit 70 is manually released and, as illustrated, is firmly supported on the base side 74 by the convex surface of the curved wall 24 with lateral border edges 76 of the emulsion side 72 of the film unit 70 in contact with the concave surface of the next of the curved walls 24. When the film unit 70 is fully inserted into the compartment 40, one edge of the film unit 70 rests and is supported upon the upper surface of support member 46 whereby the film unit 70 is prevented from passing through the open lower face 16 of the chamber 12. The rack 10 thus includes means for supporting opposed lateral border edges 76 of each film unit 70 in the form of the concave surface of the next curved wall 24, with one edge of the film unit 70 supported upon upper surfaces of support member 46, and engagement of the base side 74 upon the convex surface of the curved wall 24 of compartment 40. The emulsion side 72 of the film unit 70 is completely out of contact with the curved walls 24 or with any other film units 70 which are, of course, positioned within other compartments 40. The emulsion side 72, accordingly, is adapted to be contacted by the processing solution under agitation as provided, for example, by moving the container 60 gently to and fro.

The waste substance, e.g., sludge consisting of residual developer on the emulsion side of the film units and other waste particles released from the film units fall into the sump in the container 60s base formed by the elevation of the rack when placed within the container. The sludge is released from the lower edges of the pedestal 56 when the rack 10 is withdrawn from the container 60 and is readily rinsed away from within the sump by flushing the container 60 with clear water. The uninterrupted wall structure of the curved walls 24 and the side walls 26 prevent undue agitation of the processing solution which might pull away the softened emulsion during agitation of the container 60.

The rack is illustrated in FIG. 4 in position within the container 60. Tapering ribs 18, formed on the outer walls of the rack 10, are placed in frictional contact with inner walls 66 of the container 60 once positioned therein whereby the rack 10 is held securely within the container 60. The ribs 18 taper in a direction away from the open upper face 14 of the chamber 12 towards the open lower face 16 of the chamber thereby preventing frictional contact between the tapering ribs 18 and the inner walls 66 before the rack 10 is properly positioned within the container 60.

From the foregoing, it is apparent that the'rack 10 is competitive in cost with conventional racks and holders, durable, light weight and convenient to handle and is adaptable for use in the field, in a well equipped laboratory of the professional photographer, and in the temporary makeshift laboratory, kitchen and bathroom, of the amateur. It should be obvious to one skilled in the art that the compartments in the rack may be enlarged or reduced to accommodate therein film units of any size.

This invention may be practiced or embodied in still other ways without departing from the spirit and essential character thereof. The specific and preferred embodiments described herein are therefore to be considered illustrative and not restrictive, the scope of the invention being indicated by the appended claims and all variations which come within the meaning of the claims are intended to be embraced therein.

What is claimed is:

1. A rack for use with a container adapted to retain a supply of processing fluid therein for safe guarding and processing a plurality of individual photographic film units in sheet form, said rack comprising:

a chamber having open upper and lower faces;

means joined to inner walls of said chamber for re ceiving the plurality of film units, said receiving means including a plurality of curved walls having surfaces spaced from each other and side walls cooperating with said curved walls to provide grooves for supporting lateral edges of the film units, said curved and side walls defining a plurality of compartments adapted to retain individual film units in spaced relationship with each emulsion side of the film units exposed for free contact with the fluid; and

carrying means coupled to said receiving means including a pedestal for elevating said open lower face of said chamber above the containers base section thereby providing a sump to receive sludge and waste particles removed from the film units.

2. A rack as defined in claim 1 wherein said carrying means further includes means for detachably securing said carrying means to said receiving means.

3. A rack as defined in claim 1 wherein said pedestal further includes a plurality of support members for supporting thereon an edge of each film unit inserted into said compartments thereby preventing passage of the film units through said open lower face of said chamher.

4. A rack as defined in claim 1 wherein said pedestal further includes means defining a passage between said compartments to permit circulation of the processing fluid through said open lower face of said chamber and between said compartments of said rack.

5. A rack as defined in claim 1 wherein said side walls are defined by first portions extending from lateral edges of said curved walls and second portions integral with said first portions and converging towards each other to a surface of the next of said curved walls so as to thereby provide each of said compartments with a pair of grooves at opposite ends thereof.

6. A rack as defined in claim 5 wherein said curved walls are uninterruptedly joined between said side walls and are impervious to the passage of the processing fluid therethrough.

7. A rack as defined in claim 6 wherein outside walls of said chamber further include means for frictionally engaging a portion of the inner walls of the container to prevent lateral movement of said rack within the container.

8. A rack as defined in claim 7 wherein said frictionally engaging means are taperedfrom said open upper face towards said open lower face of said chamber thereby enabling said rack to be inserted into the container without interference from the inner walls of the container.

9. A rack for use with a container adapted to retain a supply of processing fluid therein for safe guarding and processing a plurality of individual photographic film units in sheet form, said rack comprising:

a chamber having open upper and lower faces and means for preventing lateral movement of said rack within the container;

means joined to inner walls of said chamber for receiving the plurality of film units, said receiving means including a plurality of curved walls having surfaces spaced from each other and side walls cooperating with said curved walls to provide grooves for supporting lateral edges of the film units, said curved walls and said side walls defining a plurality of compartments adapted to retain individual film units in spaced relationship with each emulsion side'of the film units exposed for free contact with the fluid with a base side of the film units supported by said curved walls, said side walls defined by first portions extending from lateral edges of said curved walls and second portions integral with said first portions and converging towards each other to a surface of the next of said curved walls, said plurality of compartments are centrally positioned about one axis of said receiving means and extend outwardly from each side of a center section of said receiving means whereat said first portion of said side walls of'each compartment adjacent to said center section is joined to a pair of laterally spaced vertical planar walls;

carrying means coupled to said receiving means including a pedestal having a plurality of support members and means defining a passage between said compartments to permit circulation of the processing fluid through said open lower face of said chamber and between said compartments of said rack, said pedestal elevating said open lower face of said chamber above the containers base section whereby a sump is formed wherein sludge and waste particles removed from the film units are deposited; and

means for detachably coupling said carrying means to said receiving means, said coupling means including means for positioning and compressively I nally parallel with said one axis within opposing wall portions of said center section for receiving and thereafter restrictively retaining said carrying means therein. 

1. A rack for use with a container adapted to retain a supply of processing fluid therein for safe guarding and processing a plurality of individual photographic film units in sheet form, said rack comprising: a chamber having open upper and lower faces; means joined to inner walls of said chamber for receiving the plurality of film units, said receiving means including a plurality of curved walls having surfaces spaced from each other and side walls cooperating with said curved walls to provide grooves for supporting lateral edges of the film units, said curved and side walls defining a plurality of compartments adapted to retain individual film units in spaced relationship with each emulsion side of the film units exposed for free contact with the fluid; and carrying means coupled to said receiving means including a pedestal for elevating said open lower face of said chamber above the container''s base section thereby providing a sump to receive sludge and waste particles removed from the film units.
 2. A rack as defined in claim 1 wherein said carrying means further includes means for detachably securing said carrying means to said receiving means.
 3. A rack as defined in claim 1 wherein said pedestal further includes a plurality of support members for supporting thereon an edge of each film unit inserted into said compartments thereby preventing passage of the film units through said open lower face of said chamber.
 4. A rack as defined in claim 1 wherein said pedestal further includes means defining a passage between said compartments to permit circulation of the processing fluid through said open lower face of said chamber and between said compartments of said rack.
 5. A rack as defined in claim 1 wherein said side walls are defined by first portions extending from lateral edges of said curved walls and second portions integral with said first portions and converging towards each other to a surface of the next of said curved walls so as to thereby provide each of said cOmpartments with a pair of grooves at opposite ends thereof.
 6. A rack as defined in claim 5 wherein said curved walls are uninterruptedly joined between said side walls and are impervious to the passage of the processing fluid therethrough.
 7. A rack as defined in claim 6 wherein outside walls of said chamber further include means for frictionally engaging a portion of the inner walls of the container to prevent lateral movement of said rack within the container.
 8. A rack as defined in claim 7 wherein said frictionally engaging means are tapered from said open upper face towards said open lower face of said chamber thereby enabling said rack to be inserted into the container without interference from the inner walls of the container.
 9. A rack for use with a container adapted to retain a supply of processing fluid therein for safe guarding and processing a plurality of individual photographic film units in sheet form, said rack comprising: a chamber having open upper and lower faces and means for preventing lateral movement of said rack within the container; means joined to inner walls of said chamber for receiving the plurality of film units, said receiving means including a plurality of curved walls having surfaces spaced from each other and side walls cooperating with said curved walls to provide grooves for supporting lateral edges of the film units, said curved walls and said side walls defining a plurality of compartments adapted to retain individual film units in spaced relationship with each emulsion side of the film units exposed for free contact with the fluid with a base side of the film units supported by said curved walls, said side walls defined by first portions extending from lateral edges of said curved walls and second portions integral with said first portions and converging towards each other to a surface of the next of said curved walls, said plurality of compartments are centrally positioned about one axis of said receiving means and extend outwardly from each side of a center section of said receiving means whereat said first portion of said side walls of each compartment adjacent to said center section is joined to a pair of laterally spaced vertical planar walls; carrying means coupled to said receiving means including a pedestal having a plurality of support members and means defining a passage between said compartments to permit circulation of the processing fluid through said open lower face of said chamber and between said compartments of said rack, said pedestal elevating said open lower face of said chamber above the container''s base section whereby a sump is formed wherein sludge and waste particles removed from the film units are deposited; and means for detachably coupling said carrying means to said receiving means, said coupling means including means for positioning and compressively retaining said receiving means between said coupling means and said support members.
 10. A rack as defined in claim 9 wherein said receiving means further includes means extending longitudinally parallel with said one axis within opposing wall portions of said center section for receiving and thereafter restrictively retaining said carrying means therein. 